NORMALIZATION: ‘1NF’ The general rule: ‘’Any field which can have many, must have its own table’’ By Sam Beaumont

What is ‘’Normalization’’? Normalization is used in any RDBMS (relational database management systems) to assist the creation of well structured, efficient databases The goal of normalisation is to divide larger tables into smaller ones. Relationships are usually defined between isolated primary keys, shared between two tables. The object of normalization is to isolate the data so that any changes (modifications, additions and/or deletions) can be done in one table, thus updating the entire database via the defined relationships between tables. ‘’Normalization’’ has several stages, they are often referred to as ‘’Normal forms’’ This presentation discusses the definition and uses of the 1 st normal form ‘1NF’

An example of relationships between tables (MS Access) Each table’s relationship is defined by common primary keys in a ‘’Many-to-one’’ or ‘’One-to-many’’ relationship

What is it used for? Normalization is used to increase the efficiency of RDBMS’ by reducing/preventing data redundancy and inconsistent dependencies. Inconsistent dependencies refer to the illogical relationship of fields in tables. For example the pet name of the pet, would not be located in the owners table. Etc. These can compromise the efficiency of a database as they are often associated to errors within the database due to broken or missing paths between the data Data redundancy is the duplication of data within the database. This can be the exact same fields/data within the same Table or several tables: IE – the replication of a Pet Owners name in various tables Redundant data wastes space, thus severely compromising the efficiency and is extremely cost inefficient

An example of splitting records and eliminating duplicated data

Therefore….. Normalisation provides: FLEXIBLE databases There are several ways to look at the data within the database, therefore not confined to existing conventions; there are several paths to reach the same data EFFICIENCY Saves space by eliminating redundant data and providing an organised structure DATA INTEGRITY ‘Modification Anomalies’ are prevented as changes made within the databases are all updated throughout due to the defined relationships. ‘Changes’ include: Deletion Addition Alteration Updates

1 st Normal Form (1NF) ‘’ALL DATA MUST BE ATOMIC’’ All fields must be atomic This means there is no duplication of data throughout the database There are no multiple values stored in one record This is done through splitting larger tables, into smaller tables, with a general and simple rule ‘’Any field which can have many, must have its own table’’ The tables are then linked by the common primary keys, defining the relationship between the two tables

An example of ‘ATOMIC’ values

Works Cited normalization.htm normalization.htm ppframe.htm ppframe.htm database_normalization_process.html database_normalization_process.html database-normalisation.html database-normalisation.html normal-forms-introduction.html normal-forms-introduction.html DataConsiten_Norm1NF.html DataConsiten_Norm1NF.html